Wireless telephone having multiple microphones

• US 8,948,416 B2
• Filed: 04/29/2009
• Issued: 02/03/2015
• Est. Priority Date: 12/22/2004
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Chen, Juin-Hwey, Bennett, James
• Primary Examiner(s): Paul, Disler
• Application Number:
  US12/432,302
• Publication Number:
  US 20090209290A1
• Time in Patent Office: 2,106 Days
• Field of Search: 381 941- 943, 381/94.7, 381/110, 381 91- 92, 381/122, 704/233, 704/226
• US Class Current: 381/94.3
• CPC Class Codes: G10L 2021/02165 Two microphones, one receiving mainly the noise signal and the other one mainly the speech signal
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H04M 1/6008 in the transmitter circuit

Abstract

The present invention is directed to a wireless telephone having a first microphone and a second microphone and a method for processing audio signal in a wireless telephone having a first microphone and a second microphone. The wireless telephone includes a first microphone, a second microphone, and a signal processor. The first microphone outputs a first audio signal, the first audio signal comprising a voice component and a background noise component. The second microphone outputs a second audio signal. The signal processor increases a ratio of the voice component to the noise component of the first audio signal based on the content of at least one of the first audio signal and the second audio signal to produce a third audio signal.

Claims

1. An audio-processing engine for use in a telephone, comprising:

a first input configured to receive a first audio signal from a first microphone, wherein the first audio signal includes a first voice signal and a first noise signal;

a second input configured to receive a second audio signal from a second microphone, wherein the second audio signal includes a second voice signal and a second noise signal; and

a signal-processing module coupled to the first and second inputs and configured to compare an energy of the first audio signal to an energy of the second audio signal in order to discriminate between voice activity and noise in the first audio signal, wherein an energy of the first voice signal exceeds an energy of the first noise signal, or an energy of the second voice signal exceeds an energy of the second noise signal, and

wherein the signal-processing module is further configured to identify time intervals of the first audio signal during which voice activity is present based on the comparison between the energy of the first audio signal and the energy of the second audio signal.

2. The audio-processing engine of claim 1, wherein the signal-processing module is further configured to compare an energy ratio between the first audio signal and the second audio signal.

3. The audio-processing engine of claim 1, wherein the first audio signal and the second audio signal undergo a frequency analysis.

4. The audio-processing engine of claim 3, wherein the frequency analysis comprises a Fast Fourier Transform.

5. The audio-processing engine of claim 1, wherein:

the first input comprises a first analog-to-digital (A/D) converter configured to convert the first audio signal from an analog form to a digital form; and

the second input comprises a second A/D converter configured to convert the second audio signal from an analog form to a digital form.

6. The audio-processing engine of claim 1, wherein the first voice signal and the second voice signal have different energy levels.

7. The audio-processing engine of claim 1, wherein the signal-processing module is further configured to suppress at least a portion of the noise of the first audio signal.

8. A telephone, comprising:

a first microphone configured to provide a first audio signal, wherein the first audio signal includes a first voice signal and a first noise signal;

a second microphone configured to provide a second audio signal, wherein the second audio signal includes a second voice signal and a second noise signal; and

a signal-processing module coupled to the first and second microphones and configured to compare an energy of the first audio signal to an energy of the second audio signal in order to discriminate between voice activity and noise in the first audio signal, wherein an energy of the first voice signal exceeds an energy of the first noise signal, or an energy of the second voice signal exceeds an energy of the second noise signal, and

wherein the signal-processing module is further configured to identify time intervals of the first audio signal during which voice activity is present based on the comparison between the energy of the first audio signal and the energy of the second audio signal.

9. The telephone of claim 8, wherein the signal-processing module is further configured to compare an energy ratio between the first audio signal and the second audio signal.

10. The telephone of claim 8, wherein the first audio signal and the second audio signal undergo a frequency analysis.

11. The telephone of claim 8, wherein the frequency analysis comprises a Fast Fourier Transform.

12. The telephone of claim 8, further comprising:

a first analog-to-digital (A/D) converter configured to convert the first audio signal from an analog form to a digital form; and

a second A/D converter configured to convert the second audio signal from an analog form to a digital form.

13. The telephone of claim 8, wherein the signal-processing module is further configured to suppress at least a portion of the noise of the first audio signal.

16. The method of claim 13, further comprising:

frequency analyzing the first audio signal and the second audio signal.

17. The method of claim 16, wherein the frequency analysis comprises a Fast Fourier Transform.

14. A method for processing audio signals in a telephone, comprising:

receiving a first audio signal from a first microphone, wherein the first audio signal includes a first voice signal and a first noise signal;

receiving a second audio signal from a second microphone, wherein the second audio signal includes a second voice signal and a second noise signal;

comparing an energy of the first audio signal to an energy of the second audio signal in order to discriminate between voice activity and noise in the first audio signal, wherein an energy of the first voice signal exceeds an energy of the first noise signal, or an energy of the second voice signal exceeds an energy of the second noise signal, and

identifying time intervals of the first audio signal during which voice activity is present based on the comparison between the energy of the first audio signal and the energy of the second audio signal.

15. The method of claim 14, wherein the comparing an energy of the first audio signal to an energy of the second audio signal in order to discriminate between voice activity and noise in the first audio signal comprises:

comparing an energy ratio between the first audio signal and the second audio signal.

18. The method of claim 14, further comprising:

converting the first audio signal from an analog form to a digital form; and

converting the second audio signal from an analog form to a digital form.

19. The method of claim 14, wherein the first voice signal and the second voice signal have different energy levels.

20. The method of claim 14, further comprising:

suppressing at least a portion of the noise of the first audio signal.